I'm running a C6 Flexplate on mine, so yes, it can be done. The bolt circle and offset are the same.
E4ODs up to 1991 also use the heavy cast iron C6 style, 2-piece setup. Then they switched over to a simplified and lighter combined flywheel/flexplate for 1992 and up.
For the driveshafts, you may be able to simply find them in a wrecker or donor truck, since you aren't actually changing to some new exotic size. The size you would need was mass produced for the E4OD trucks.
Having a trans shop do the swap would cost more than a regular transmission install. The cross member has to move back (ideally replaced as well, to the later E4OD style) and that will require drilling on the frame. They may not want to do this, for liability reasons. I also cut and extended the shift rod from my old C6 transmission but you can probably get the correct parts from another E4OD donor.
Plan on about $600 for a new controller and harness from US Shift, unless you luck out and find a used setup. Some have even made the OEM setup work in an older truck. This might be cheaper if you can find a donor, but will get complicated if you can't get everything to work perfectly.
Like I said, it won't be cheap. But with inflation driving the cost of everything up, neither will diesel fuel...